Diaper with opening in top sheet

ABSTRACT

A diaper having a front part (12), a back part (14) and an intermediate crotch part (13) which includes an absorbent body unit (1) which is joined to a fluid-impermeable bottom sheet (7) and to a fluid-permeable top sheet (9) which lies proximal to the wearer&#39;s body in use and which includes an opening (15) situated in the back part and crotch part of the diaper and stretch-mounted elastic devices (20, 21), and which is not attached to the absorbent body unit at least within the region of the opening (15). The absorbent body unit (1) includes a main body (2) which is provided with a leg recess on respective sides thereof, and two side-bodies (3, 4) which are placed laterally outside the main body on respective sides thereof and in respective leg recesses. The absorbent body unit (1) is enclosed between the bottom sheet (7) and an inner casing sheet (8) made of fluid-permeable material, the sheets being mutually joined at parts which lie outside the absorbent body unit and carry stretch-mounted elastic elements (10, 11) along their respective side edges within at least the central part of the diaper. Each side-body (3, 4) has an arcuate edge on that side (22) thereof which lies proximal to a respective leg recess in the main body (2). The side-bodies are spaced from the main body (2); and the inner casing sheet (8) is joined to the bottom sheet (7) in those gaps that are formed in the leg recesses between the main body and the side-bodies.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is filed under 35 U.S.C. § 371 as the national stageapplication of International application PCT/SE94/01178, filed on Dec.8, 1994, which designated the United States of America.

FIELD OF THE INVENTION

The present invention relates to a diaper having a front part, a backpart and an intermediate crotch part which includes an absorbent bodywhich is joined to a fluid-impermeable bottom sheet and to afluid-permeable top sheet which lies proximal to the wearer's body inuse and which includes an opening situated in the back part and crotchpart of the diaper and stretch-mounted elastic devices, and which is notattached to the absorbent body at least within the region of saidopening, wherein the absorbent body includes a main body which isprovided with a leg recess on respective sides thereof, and twoside-bodies which are placed laterally outside the main body onrespective sides thereof and in respective leg recesses.

BACKGROUND OF THE INVENTION

One such diaper is known from EP-A2-0,486,006 and is intended to avoidirritation of the wearer's skin as a result of excrement or urine cominginto contact therewith. According to this publication, this is achievedby deformation of the absorbent body into a basin-like shape as theelastic devices provided in the top sheet contract, at the same time asthe top sheet is distanced from the bottom of the basin and forms anapertured basin lid or cover. One problem with diapers of this kind isthat the opening or aperture in the top sheet must be so large and sopositioned as to ensure that excrement from the wearer will fall downonto the absorbent body. If excrement lands on the top sheet, there is aserious risk of leakage and irritation of the skin. Another problem isone of constructing the diaper so that the diaper will be deformedappropriately as the top sheet is shortened by contraction of theelastic devices, and to prevent the whole of the absorbent body cominginto abutment with the top sheet during the use of the diaper.

An object of the present invention is to solve or at least greatlyreduce these problems.

SUMMARY OF THE INVENTION

This object is achieved in accordance with the invention with a diaperof the kind defined in the introduction which is characterized in thatthe absorbent body is enclosed between the bottom sheet and an innerfluid-permeable casing sheet, said sheets being joined mutually at partswhich lie outside the absorbent body and carry stretch-mounted elasticelements along their side edges within at least the central part of thediaper; in that each side-body has an arcuate edge on the side thereofproximal to the leg recess of the main body; in that the side-bodies arespaced from the main body; and in that the inner casing sheet is joinedto the bottom sheet in those gaps that are formed in the leg recessesbetween the main body and the side-bodies.

According to one preferred embodiment of the invention, the main body ofthe absorbent body includes an upper layer which lies proximal to thetop sheet and a bottom layer which extends longitudinally at least alongthe leg recesses of the main body and has greater rigidity than the toplayer. The sides of the side-bodies that lie distal from the legrecesses in the main body also have arcuate edges and the side-bodiesare made from an absorbent deformable material. When the diaper is heldflat with elastic devices and elements stretched, the sides of theside-bodies distal from the main body will preferably have straightedges. In one variant, the circle-segmental side-bodies include a row ofwedge-shaped recesses on the straight side thereof distal from the mainbody.

BRIEF DESCRIPTION OF THE INVENTION

The invention will now be described in more detail with reference to theaccompanying drawings, in which

FIG. 1 is a perspective schematic view of a first embodiment of aninventive diaper seen obliquely from above;

FIG. 2 illustrates the diaper of FIG. 1 schematically from above andshows the diaper in a flat state;

FIG. 3 is a schematic cross-sectional view of the diaper illustrated inFIG. 1;

FIG. 4 is a view corresponding to the view in FIG. 2 showing the bottomsheet and the absorbent body of the diaper illustrated in FIG. 1;

FIG. 5 is a view corresponding to the view in FIG. 2 and illustrates asecond embodiment of an inventive diaper;

FIGS. 6 and 7 illustrate different embodiment of side-bodies suitablefor use in an inventive diaper; and

FIG. 8 is a view similar to the view in FIG. 4 and illustrates aninventive absorbent body provided with side-bodies according to FIG. 6.

DETAILED DESCRIPTION OF THE INVENTION

The diaper illustrated in FIGS. 1-4 includes an absorbent body unit 1which is comprised of a main body 2 of hourglass configuration and twoside bodies 3, 4. The main body 2 is comprised of two layers 5, 6 ofwhich the upper layer 5, and also the side-bodies 3, 4, are comprised ofair-laid cellulose fluff, whereas the bottom layer 6 includes anabsorbent reel material of the kind described in Swedish PatentApplication No. 9203445-3, which contains a dry formed sheet containing5-100% cellulose fibres having a bulk density of between 0.2-1.0 g/cm³and a surface weight of between 30-2000 g/cm² and which is formed bycompressing a web containing cellulose fibres without subsequentdefibration and fluff forming. The reader is referred to theabove-mentioned application for closer details of such reel material. Aswill be seen from FIG. 4, the layer 6 is rectangular in shape andextends only beneath part of the layer 5. It will be understood,however, that the layer 6 may have other shapes than rectangular, forinstance the layer 6 may have an hourglass shape, T-shape, etc.,conforming to the layer 5. The layer 6 may also be given a greaterextension longitudinally, for instance it may be given the same form andextension as the layer 5. It is not necessary that the layer 6 becomprised of absorbent material, even if this is to advantage, and it isalso possible to exclude this layer entirely when the remainder of theabsorbent body has the desired stiffness or rigidity.

The absorption body unit 1 is enclosed between an outer casing sheet orbacking sheet 7 of liquid-impermeable material, such as polyethyleneplastic for instance, and an inner liquid-permeable casing sheet 8,which is preferably comprised of nonwoven material. The inner sheet 8and the backing sheet 7 are preferably of identical shape and are joinedtogether at parts which lie outside the absorbent body 1. As will bestbe seen from FIG. 4, the side-bodies 3, 4 are positioned laterallyslightly outside the main body 2 and the casing sheets 7, 8 are mutuallyjoined in the gaps between the main body and the side bodies.

The diaper also includes a top sheet 9 whose shape is identical to theshapes of the casing sheets 7, 8 and which is fastened to said sheetsalong diaper edge parts, so that the top sheet will be generally freefrom the absorbent body 1, i.e. generally unattached thereto. Asillustrated in FIGS. 1 and 2, the diaper includes leg elastic in theform of elastic devices 10, 11 which extend along the side edges of thecrotch part 13 and along parts of the front diaper part 12 and the backdiaper part 14. In the illustrated embodiment, the elastic devices arecomprised of four elastic threads which are attached in a stretchedstate between the top sheet 9 and the inner casing sheet 8 and fastenedto said sheets. It will be understood that the number of leg elasticsused may be greater or fewer than four threads, and that other types ofelastic devices may be used, such as elastic bands or ribbons, bands offilm material that has elastic properties, etc. It will also beunderstood that the elastic devices 10, 11 may be mounted between thebottom sheet 7 and the inner casing sheet 8 instead.

An opening 15 is formed in the top sheet 9 symmetrically in relation tothe longitudinal direction of the diaper. The front edge 16 of thisopening is located between the wetting point and the excretion point. Bywetting point is meant that region of the diaper within which urinedischarged by the wearer is expected to be deposited when the diaper iscorrectly positioned on the wearer, and by excretion point is meantcorrespondingly that region of the diaper within which faeces will bedeposited on a correctly positioned diaper, i.e. those regions which lieopposite to the external urethra orifice and the anus of the wearer,while taking into consideration normal variations in the wearer'sanatomy within the size ranges of the wearer for which the used diaperis dimensioned. The side edges 17, 18 of the opening 15 extenddivergently away from one another in a direction towards the back diaperpart, and the rear edge 19 of the opening is arcuate in shape andlocated in the back diaper part at a short distance from the rear end ofthe absorbent body.

Two elastic threads 20, 21 are fastened in a stretched state to the topsheet 9 and extend from the forward part of the front diaper part 12 tothe rear part of the back diaper part 14. The threads 20, 21 extendmutually convergent from the front part 12 to the forward edge 16 of theopening 15 and then extend along the side edges 17, 18 of the openinggenerally on the same level as the rear edge 19 of the opening. In theillustrated embodiment, the threads 20, 21 are mounted between the topsheet and narrow strips of nonwoven material (not shown) which arefastened to the threads and the top sheet with the aid of glue or bysome other suitable means. In the illustrated embodiment, the strips aredisposed along the full length of the threads and are thus fastened tothe top sheet along the whole of its length. This is not absolutelynecessary, however, since the desired function can be achievedsufficiently well when the threads are fastened to the top sheet attheir respective ends and on both sides of the front edge.

In one variant of the invention, the nonwoven strips are fastened to thetop sheet at their respective edges so as to form guide passages forelastic threads extending therethrough. In the case of this embodiment,it is sufficient to fasten the threads to the top sheet at the ends ofthe passages. For instance, if the nonwoven strips extend along the fulllength of the elastic threads it is sufficient to fasten the ends of thethreads to the tops sheet. It is preferred that the threads will extendfreely in the guide passages, at least along the edges of the opening15. When the top sheet lacks the provision of guide passages forwardlyof the opening 15, the nonwoven strips can be formed unitary with thetop sheet, by folding said top sheet in conjunction with cutting out theopening 15. In this case, the provision of separate nonwoven strips infront of the opening can be omitted, in which case the threads will liefreely between their forward top sheet attachment points and the ends ofthe passages at the forward edge of the opening. As will be understood,it is also possible to fasten the threads to the top sheet along thewhole of that part thereof which extends in front of the opening, forinstance by attaching separate nonwoven strips.

FIG. 2 illustrates the diaper in a flat state, i.e. the state in whichthe diaper is found during manufacture, in which the diaper is heldstretched against the action of the spring force exerted by the elasticdevices. When the finished diaper is released from its stretched state,the elastic devices 10, 11, 20 and 21 strive to contract to atensionless or relaxed state, therewith deforming the diaper to theshape illustrated in FIGS. 1 and 3.

Contraction of the elastic threads 20, 21 causes the top sheet to gathertogether and therewith shorten. In order to allow this shortening of thetop sheet to take place, the main body 2 of the absorbent body unit 1 iscurved at the same time as the side bodies 3, 4 are swung upwards abouthinge means formed by the casing sheets 7, 8, these sheets being joinedin the gaps defined between respective side bodies 3, 4 and the mainbody 2. Thus, the elastic threads 20, 21 are instrumental in maintainingthe top sheet 9 in spaced relationship with the absorbent body 1. Theprovision of the bottom layer 6, which is stiffer than the layer 5 ofthe absorbent body 1, ensures that the main body 2 will not be foldedwhen the top sheet is gathered, but obtains an even curvature.

It is mentioned in this respect that FIG. 1 illustrates the diaper whenno load is exerted thereon, and thus not when the diaper is worn. Aswill be understood, the shape adopted by a diaper when in use willdepend on the anatomy of the wearer, and the diaper is so dimensionedthat the elastic threads 20, 21 will normally be stretched slightly asthe diaper is placed in position on the wearer. However, the length ofthe diaper is such that a large part of the fold or gather in the topsheet will remain after having put on the diaper, so that the absorbentbody will be located at a distance from the top sheet along a greaterpart of its extension, even after having put the diaper on.

Thus, there is found between the absorbent body and the top sheet aspace in which excrement i.e. faeces is kept out of contact with theskin. Furthermore, it must be ensured that excrement is deposited inthis space and not on the top sheet, and it will therefore be understoodthat the size and positioning of the opening are of decisive importance,particularly with regard to the excrement point. It has been found thatthe distance between the side edges 17, 18 of the opening should be atleast 3 cm at the excrement point, and that the front edge of theopening 15 should lie at least 1 cm and preferably 2 cm forwardly of thefront edge 16, and that the front edge 16 should be at least 2 cm long.Because the elastic threads 20, 21 exert a spring force in both thelongitudinal and transverse directions of the diaper when the diaper isworn, the front edge of the opening 15 and its side edges 17, 18 will bestretched outwardly so as to ensure that the aforesaid distances areretained when the diaper is in use. In order to achieve a high outwardtensioning effect, the ends of the threads 20, 21 will preferably lie onthe same level as the side edges of the absorbent body 1 essentially ina lateral direction.

In addition to gathering together the top sheet 9, the elastic threads20, 21 also have a sealing function by lying sealingly against thewearer's body when the diaper is worn. This greatly reduces the risk ofdischarged urine running along the top sheet instead of passing throughsaid sheet and being absorbed by the absorbent body in the mannerintended. The fact that the elastic threads extend along the side edgesof the opening also greatly reduce the risk of the position of theopening 15 being changed as a result of external forces on the diaper,for instance as the wearer of the diaper moves. An added advantage isthat when the absorbent body is subjected to an external load andsubsequently pressed towards the body of the wearer, it is moredifficult for excrement to seep over the edges of the opening 15 andonto the top sheet 9. In order to obtain these sealing functions, it hasbeen found that the distance between the side edges 17, 18 of theopening 15 at the centre of the excrement point should not exceed 6 cmand will preferably be smaller than 5 cm. The length of the front edge16 of the opening 15 will preferably not exceed 4 cm.

From the aspect of absorption, the side bodies 3, 4 are not joined tothe remainder of the absorbent body 1 and form safety bodies whichabsorb fluid when the main body 2 becomes saturated or is unable toabsorb discharged fluid for some reason or another. In addition to thisfunction, the side bodies also contribute to the stability of the basinthat is formed when the top sheet is gathered together and prevent themain absorbent body in its entirety coming into abutment with thewearer's body when the diaper is subjected to an external load, as willbe described below.

FIG. 5 illustrates a second embodiment of an inventive diaper in a viewcorresponding to the view of FIG. 2. Diaper components corresponding tothe FIG. 2 embodiment have been identified with the same reference signsto which a prime has been added. In the case of the diaper illustratedin FIG. 5, the elastic threads 20', 21' cross one another in front ofthe opening 15' in the top sheet 9', and the opening is terminatedforwardly in a point. The opening 15' thus has a punctiform front edge.In other respects, the diaper illustrated in FIG. 5 has the sameconstruction as the diaper illustrated in FIGS. 1-4.

An extremely good sealing function can be achieved by the top sheet 9'as a result of the mutually crossing threads 20',21'. The point ofintersection of the elastic threads 20', 21' shall lie between thewetting point and the excrement point and the same requirements as thoseplaced on the diaper according to FIGS. 1-4 with regard to the distancebetween the side edges of the opening 15 at the excrement point alsoapply to the opening 15'. Accordingly, the point of intersection willlie relatively close to the wetting point, meaning that the illustratedembodiment cannot be worn readily by males, since space must be foundbetween the elastic threads 20', 21' to accommodate the scrotum.Naturally, it is possible within the scope of the present invention tomodify the extension of the threads within the region of the wettingpoint so as to prepare room for the scrotum.

When the diaper is worn, the absorbent body 1 can be likened to aflat-bottom boat or punt, where the main body 2 forms the bottom and theside-bodies 3, 4 form the freeboard of the "punt". Thus, when the diaperis worn, that side 22 of the side-bodies 3, 4 which lies proximal to themain body, or in other words the underside 22, shall have a curvaturewhich corresponds to the curved shape that the main body shall take inorder to form a suitable space between the absorbent body and the topsheet, which when the diaper is worn conforms to the shape of thewearer's body. The upper side 23 of the side-bodies shall thus have asmaller curvature which corresponds to the curvature of the wearer'sanatomy.

Side-bodies 3, 4 which fulfil these requirements are obtained with theillustrated embodiments of the invention by giving the undersides 22 ofthe side-bodies an initial appropriately curved form and bymanufacturing the same from a relatively soft and deformable material.As the elastic devices of the diaper illustrated in FIGS. 1-4 contract,the diaper will pass from the flat state illustrated in FIG. 4 to thestate illustrated in FIG. 1. In this respect, contraction of the legelastic devices 10, 11 causes the side-bodies 3, 4 to swing upwardsaround their hinges, formed by those parts of the layers 7, 8 joined inthe gaps between the main body 2 and the side-bodies, and also deformsthe upper sides 23 of the side-bodies into a curved shape. Contractionof the elastic threads 20, 21 in the top sheet 9 does not affect theside-bodies to any great extent, but merely causes the main body 2 tocurve. Consequently, the invention is not restricted to a top sheetwhich includes elastic threads arranged in the patterns illustrated inFIGS. 2 and 5, but can be applied with all diapers provided with elasticdevices that create folds or puckers in the top sheet, so that the topssheet will be distanced from the absorbent body.

When a diaper is worn by the user, the side-bodies prevent externalloads on the diaper, at least within the crotch part, from pressing themain body into abutment with the top sheet and ensure that a givenstorage space will always remain. Because the underside of theside-bodies conform generally to the curved shape of the main body andthe upper side of said side-bodies conform to the shape of the wearer,deformation due to external loads, for instance as the wearer of thediaper sits down, takes place essentially by compression and/or inwardswinging of the side-bodies and the change in curvature of the mainbody. Furthermore, as a result of the described configuration of theside-bodies, the pressure at which the side-bodies abut the wearer'sbody will be uniformly distributed both in the absence of load on thediaper and when the diaper is subjected to external forces, therewithproviding a comfortable diaper and reducing the risk of the diaperchafing against the skin of the wearer within the region of theside-bodies.

FIG. 6 illustrates an embodiment of a side-body 103 which differs fromthe side-bodies illustrated and described above, in that the side-bodyis initially given a crescent-like shape with a curved upper side 123,this curve corresponding generally to the shape of the wearer's body,and an underside 122 which has a curvature corresponding to the desiredcurvature of the main body, as in the earlier case.

FIG. 7 illustrates another embodiment of a side-body 203 which has a rowof wedge-shaped recesses 224 formed in its upper part. When a side-bodyof this kind is used in a diaper which in other respects is constructedin the same manner as the diaper illustrated in FIGS. 1-4, contractionof the leg elastic will deform the side-body to the shape illustrated inbroken lines in FIG. 7.

FIG. 8 is a view similar to the view of FIG. 4 and illustrates a thirdembodiment of an inventive diaper. This embodiment differs from theearlier described embodiments primarily in that crescent-shapedside-bodies 103, 104 having curved upper sides are used instead ofside-bodies that have straight upper sides. The undersides 122 of theside-bodies 103, 104 also have a greater curvature than the leg recessesof the main body 102, which means that the gap between main body andside-bodies will have a varying width. It will be seen that when the topsheet of such a diaper is gathered together, the basin that is formed bythe main body 102 and the upraised side-bodies 103, 104 will be deeperthan the basin that is formed in the diaper illustrated in FIG. 1. Thedepth of the basin formed can be varied by varying the curvature of theunderside of the side-bodies.

From an absorption aspect, the side-bodies 103, 104 of the FIG. 8embodiment may be joined to the main body by four narrow strings orbridges 125 of absorbent material, through which fluid can be drawn bysuction from the main body 102 by the side-bodies 103, 104 when the mainbody is saturated in the sensitive crotch part.

It will be noticed that the term "diaper" as used in the presentdocument is intended to include so-called pants-type diapers andincontinence guards for people suffering double incontinence.

It will be understood that the illustrated and described embodiments canbe modified within the scope of the present invention. For example, theside-bodies can be made of a stiffer material, for instance the samematerial as the bottom layer 6 of the main body or tissue, when theupper sides of said side-bodies are formed in accordance with theembodiments of FIGS. 6 and 7 rather than said upper sides being straightinitially. It is not necessary that the side-bodies be made of anabsorbent material, even though this is preferred. Naturally, the upperpart of the side-bodies may conceivably be formed from a softer materialthan the bottom part. The side-bodies need not extend beyond the outerside extremity of the main body, and the outer side edges of saidside-bodies may extend flush with said outer side extremity or may eventerminate short thereof. The invention is therefore restricted solely bythe content of the following claims.

We claim:
 1. A diaper extending in a longitudinal direction andcomprising:a front part, a back part, and an intermediate crotch part,an absorbent body unit joined to a fluid-impermeable bottom sheet, andto a fluid-permeable top sheet which lies proximal to a wearer's body inuse, said top sheet including an opening situated in the back and crotchparts of the diaper, and stretch-mounted elastic devices, said top sheetbeing unattached to the absorbent body unit at least within the regionof the opening, said absorbent body unit including a main body providedwith a leg recess on respective sides thereof, and two side-bodiesplaced laterally outside the main body on respective sides thereof andin respective leg recesses, said absorbent body unit being enclosedbetween the bottom sheet and a fluid-permeable inner casing sheet, saidbottom and inner casing sheets being mutually joined at parts which lieoutside the absorbent body unit and carry stretch-mounted elasticelements along their respective side edges within at least a centralpart of the diaper; each side-body having an arcuate edge on that sidethereof which lies proximal to a respective leg recess in the main body,the side-bodies being spaced from the main body, and the inner casingsheet being joined to the bottom sheet in those gaps that are formed inthe leg recesses between the main body and the side-bodies.
 2. A diaperaccording to claim 1, wherein the main body of the absorbent body unitincludes an upper layer which lies proximal to the top sheet and a lowerlayer which longitudinally extends at least along the leg recesses ofthe main body, said lower layer having a greater rigidity than the upperlayer.
 3. A diaper according to claim 1, wherein those sides of theside-bodies which lie distal from the leg recesses of the main body alsohave arcuate edges.
 4. A diaper according to claim 3, wherein theside-bodies are made of deformable material.
 5. A diaper according toclaim 4, wherein when the diaper is held flat with the elastic devicesand elastic elements held stretched, the sides of the side-bodies distalfrom the main body have straight edges.
 6. A diaper according to claim1, wherein the side-bodies include a row of wedge-shaped recesses onthat side thereof distal from the main body.
 7. A diaper according toclaim 4, wherein when the diaper is held flat with the elastic devicesand elastic elements held stretched, the side-bodies have acrescent-like shape, and respective sides of the side-bodies that lieproximal to and distal to the main body have a curved edge.
 8. A diaperaccording to claim 1, wherein the side-bodies are made from absorbentmaterial.
 9. A diaper according to claim 8, wherein the side-bodies arejoined to the main body by bridges of absorbent material.